Hydraulic fly-press.



No. 819,988. PATENTED MAY 8, 1906. B. GERDAU. HYDRAULIC FLY PRESS.

APPLICATION FILED 00T.11, 1899.

Cg W 3 5- i rrf irn-n STATES PATENT OFFICE.

Specification of Letters Patent.

Patented May 8, 1906.

Application filed October 11, 1899. Serial No. 733,242.

To all whom it nuty concern: 1

Be it known that I, BERTHOLD GERDAU, a subject of the King of Prussia, German Emperor, residing at Dusseldorf, in the Kingdom of Prussia, Germany, have invented certain new and useful Improvements in Hydraulic F ly-Presses, of which the following is a specification.

This invention relates to a hydraulic flypress which is so constructed that the press or the purposes of rapid operation is not only connected to the pressure-producing device or with the means for admitting pressure to' the pressure-cylinder, but also with a second feeding conduit for the pressure cylinder,

- and which is exposed to the pressure of a special pressure-accumulator in such a manner that the return-cylinders are connected to this feeding-conduit and through the same with a collector for an elastic-pressure fluid, Which latter is capable of being shut ofi' from the feeding-conduit by means of an automatic closing device. The distinguishing feature of this new combination is that the pressure below the return-piston and in the elasticpressure collector is never capable of becoming reduced below the accumulator-pressure in the feeding-conduit, so that even the greatest carelessness on the part of an attendant in case of leaks cannot cause any damage. This feature will exist also in case of pressure liq uid being caused to flow out from the return- 0 linders and from the feeding-conduit to the rear of the pressure-piston for the purposes of a displacement of the pressurepistons by positive means and by means of a controlling device specially inserted for the said purpose.

The accompanying drawing is a vertical longitudinal section, partly in side view, of my improved hydraulic fly-press.

The letter (1 represents a working cylinder provided with piston b and a pressure-plum ger d. The cylinders e e of the return-pistons f f, connected to the working piston, are in communication with a special pressure-com duit g h, which is independent of the press itself. At the part it of this conduit h and near to the return-cylinders a receptacle i is arranged, which contains air under pressure, 800., for the purpose of direct action upon the said hydraulic conduit. Special hydraulic pressure is produced by any suitable devicey an accumulator Z, for instanceand the conduit 9, through which the pressure fluid passes into the conduit h, is shut ofl' from the said conduit bya check-valve m, situated at the entrance of the conduit h.

To the pipe-conduit h, and consequently also to the vessel i and with the pressure-accumulator Z, a circuit-pipe conduit n is connected, which leads -to a special hydraulic controlling-valve 0 p g and thence through the pipe 1 into the working cylinder a of the press at the rear of the piston b in order to be able to regulate the adjustment of the same for the length of the stroke just required. This special hydraulic controlling-valve consists 0 two casings 0 and p and of the casing g for the adjoining check-valvev Within the casing 0 the piston l is movable in the bore 2. This bore is provided with a number of lateral outwardly-opening passages, of which passage 3 is intended for establishing communication with the pressure-conduit n, passage 4 for communication with the second casing p, the passage'5 for communication with the valve q, and 6 is the water-escape passage.

The piston 1 is'coupled to a piston 7 in the in-' terior ofcasing p, and this piston moves in a bore 8, from which a lateral communicating passage 9 leads-to a conduit 10 and into the lower part of the casing g, while another passage 11 constitutes a water-esc ape. In the interior of the casing q, in the upper part of the same, the valve-cone 13 is guided by means of the rod 12. The bottom part of the casing is shaped into a small cylinder 14, surrounding a piston 15, the lifter 16 of which. reaches as far as below the valve-cone 13 and is capable of lifting the valve for the purpose of opening the same. The movement of the valve 13 takes placeiautomatically, the drawing showing said valveraised ofi its lifter 16 by the pressure of the water flowing from passage 5 to cylinder a. The movement of the two pistons 1 and 7from the position of the passing through of the pressure water into the position of the escape of the water or into the inoperative position is effected by means of the hand-lever 17.

The operation of the apparatus is as follows: The parts are normally in the position indicated in Fig. 1, but with port 5 closed by valve 1. When the pressplunger is to be advanced', valve 1 is raised to the position shown in said figure, and water under accumulatorpressure passes to cylinder at, check-valve 13 rising to permit such passage, the greater area of the upper end of plunger 1) overcoming the area of the lifting-pistonsf, water circulating from cylinder 6 to cylinder a, and air being v is then withdrawn. To ralse the press-plum ger, valve 1 is lowered to a osition beneath port 5,-pening port to ex aust port 6 and also depressing valve 7, so as to open port 9" to pressure from pipe 4 and p st 3', the pr s sure thereby admitted beneath piston 1'5- lift= ing and holding 0 en cneek valw was long as may be deslre the water in cylinder a then exhausting through the assa e and port's set forth. The pressure s cylinder at sing relieved, the air in vessel immediately expands, imparting a uick return move-- ment to the lifting pistofis' we pr'ess plum ger'. Valve 1 is then returned to normal or intermediate position.-

1, In a hydraulic press, the combination with a ressureaaccumulator and withdrawal or return cylinders connected therewith, and with a' ressure-ra'm cylinder or working'piston-'cyl ruler, of a pressure-conduit connectin the withdrawal of return cylinders with said ressure-ram, a separate pressure-chamber containing an elastic fluid on said conduit for the accumulator may be out offfro'm said pressure-conduit, substantially as s 2. In a hydraulic press, the com ination with a pressure aocumulator and Withdrawal or return pistons rigidly connected to the working iston or ram; of a separate pressure=con ui-t between the working piston or ram 'cylind er' and! the cylinders 0*? the return "istons, a separate chamber on said conduit flee with an elastic fluid, a pipe i termediate the aid chamber and the waking eylin dr and connecting with the accumulator, and controllin -valve mechanism in the cow dui't, said va 6 mechanism comprising, a

check-valve, the eheckwaive having a mo tor=pistoa, and connections for lifting the valve insxhausting the press, substantially as specified. v

In witness whereof I have herwnto s1 med my name in the presence of two subseri 'ing witnesses. n

BERTHOLE GERDAU. Witnesses:

WILLIAM Essmswsm, Gm. P. Pawn. 

